A philatelic term referring to an envelope with a postage stamp that was issued on the first day the stamp was officially available.

डाक टिकट के पहले दिन जारी की गई एक लिफाफे।

English Usage: The collector showed me his prized first day cover from the 1960s.

Hindi Usage: संग्रहकर्ता ने मुझे 1960 के दशक का उसका बहुमूल्य प्रथम दिवस कवर दिखाया।